What Is the Smallest Thing You Would Still Call a Hill?

Start with something obviously a hill and take a metre off it. Still a hill. Take another metre. Still a hill. Keep going, one metre at a time, and at no single step does it stop being one — and yet at the end you are standing in front of a slight rise in a field that nobody would dignify with the word.

This is an old problem and it has an old name. It works the same for heaps of sand, for beards, for a warm bath and for being late. The trouble is not that we lack a measurement. It is that we are using a word which was never built to have an edge, and then acting surprised when it does not have one.

What actually decides it is not height at all. It is effort and consequence: whether you notice it in your legs, whether a bicycle changes gear, whether the view is different at the top. A three-metre bump in a flat county is unmistakably a hill. A thirty-metre one halfway up a mountain is a bulge in the path and nobody names it.

So the answer is that a hill is not a size. It is a relationship between a piece of ground and somebody walking up it, and the same lump of earth can be a hill on a tired evening and nothing at all on a good morning.